Semiconductor devices are used in a variety of electronic applications, such as personal computers, cell phones, digital cameras, and other electronic equipment. Semiconductor devices are typically fabricated by sequentially depositing insulating or dielectric layers, conductive layers, and semiconductor layers of material over a semiconductor substrate, and patterning the various material layers using lithography to form circuit components and elements thereon.
As the semiconductor industry has progressed into nanometer technology process nodes in pursuit of higher device density, higher performance and lower costs, challenges from both fabrication and design issues have resulted in the development of three-dimensional designs, such as the fin field effect transistor (FinFET). FinFETs are fabricated with a thin “fin” or “fin structure” vertically extending from a substrate, and a gate electrode is formed over the fin. Thus, the channel of the FinFET is formed. However, following a series of manufacturing operations, the fin structure may have some structure losses and thus impacts the electron mobility in the channel.